My old alloy Mog when restored circa 20 years ago was rebuilt using stainless screws nuts and bolts which have as yet not displayed any real issue in terms of corrosion. OK so I have not covered more than circa 28k miles in that time, however it has been exposed to wind rain and even snow on occasion. I suspect the reason for it`s present tidy condition is down to both the experience that Kevin, ( the restorer) has had over the years resolving Morgan corrosion issues on other folks Morgans, the benefit of which was utilised when he got round to rebuilding a +8 for himself, in that he well knew where to put in the extra effort to reduce the effects of corrosion..
Anyone who has ever painted a panel held on by screws knows well that the threads of the screw will dislodge some if not all of the paint from within the hole as the screw is pushed through it and that is where the corrosion can begin. Of course it is possible to utilise some assembly goo to offset this effect, but it seems in time corrosion is likely to begin therein..?
I posted a couple of close up pics in the galleries of fixings on my car which have eventually begun to shown marginal signs of corrosion, though the majority have not.
https://www.tm-img.com/image/xyNSahttps://www.tm-img.com/image/xy726Elsewhere I have indeed seen stainless fixings utilised in aluminium, which totally seized up in time when exposed to the elements continuously..